Table S1: Chemical species used for calculating speciated OH reactivity Compound/ Chemi- kM+OH [cm³ Instrument Compounds attributed to If no unambiguous Literature reference for Max. OH Comment protonated mass cal molecules-1 protonated mass compound reaction rate coefficent reactivity -1 (grey shaded formula s ] identification: during compounds are gas reaction rate AQABA standard calibrated coefficient derived [s-1] with low uncertainty) from… Alkanes Methane CH4 6.45E-15 Picarro Cavity IUPAC preferred value 0.35 ring-down spectroscopy instrument Ethane C2H6 2.40E-13 GC-FID IUPAC preferred value 0.26 Propane C3H8 1.10E-12 GC-FID IUPAC preferred value 1.33 2-Methylpropane C4H10 2.12E-12 GC-FID Atkinson and Arey, 2003 0.68 n-Butane C4H10 2.35E-12 GC-FID IUPAC preferred value 1.42 2-Methylbutane C5H12 3.60E-12 GC-FID Atkinson and Arey, 2003 0.92 n-pentane C5H12 3.80E-12 GC-FID Atkinson and Arey, 2003 1.03 2-Methylpentane C6H14 5.20E-12 GC-FID Atkinson and Arey, 2003 0.11 n-hexane C6H14 5.20E-12 GC-FID Atkinson and Arey, 2003 0.16 2,2,4- C8H18 3.34E-12 GC-FID Atkinson and Arey, 2003 0.004 Trimethylpentane n-heptane C7H16 6.76E-12 GC-FID Atkinson and Arey, 2003 0.06 Octane C8H18 8.11E-12 GC-FID Atkinson and Arey, 2003 0.04 Alkenes and Alkynes Ethene C2H4 7.50E-12 GC-FID IUPAC preferred value 2.26 Propene C3H6 2.90E-11 GC-FID IUPAC preferred value 1.11 trans-2-butene C4H8 6.40E-11 GC-FID IUPAC preferred value 0.11 1-Butene C4H8 3.14E-11 GC-FID IUPAC preferred value 0.26 1-Pentene C5H10 3.14E-11 GC-FID Atkinson and Arey, 2003 0.10 Isoprene C5H8 1.00E-10 GC-FID IUPAC preferred value 0.76 27.023 C2H2 7.50E-13 PTR-ToF-MS Ethyne IUPAC preferred value 0.001 41.0386 C3H4 6.95E-13 PTR-ToF-MS Propyne; 1,2-Propadiene average Warnatz, 1984; Atkinson and 0.27 Arey, 2003 67.0543 C5H6 5.16E-11 PTR-ToF-MS 1,3-Cyclopentadiene; 3- average Grosjean and Williams, 1992; 0.35 penten-2-yne Boodaghians et al., 1987 69.0699 C5H8 5.10E-11 PTR-ToF-MS 1-Pentyne; 1,2-Pentadiene; average Boodaghians et al., 1987; 1.92 C5 dienes. 1,4-Pentadiene; 1,3- Rogers, 1989; Ohta, 1983; Isoprene Pentadiene; Cyclopentene Atkinson and Arey, 2003 measured by GC- FID was subtracted 83.0856 C6H10 8.69E-11 PTR-ToF-MS Cyclohexene, 1-methyl- average Atkinson and Arey, 2003; 3.13 C6 dienes cyclopentene; 2,3- Boodaghians et al., 1987 dimethylbutadiene; 2-methyl- pentadiene; hexyne; 2-methyl- 1,4-pentadiene; 3-methyl-1,3- pentadiene; 4-methyl-1,3- pentadiene; 1,2-hexadiene; 2- 4-hexadiene; 1,4-hexadiene; 1,3-hexadiene; 1,5-Hexadiene 85.1012 C6H12 6.63E-11 PTR-ToF-MS 2-Methyl-2-pentene; 2- average Atkinson and Arey, 2003 0.57 C6 alkenes Methyl-1-pentene; 3-Methyl- Ohta, 1983; Grosjean and 2-pentene; 2-Ethyl-1-butene; Williams, 1992 2,3-Dimethyl-2-butene; 1- Hexene; 2-Hexene; 3-Hexene; 4-Methyl-2-pentene 95.0856 C7H10 4.68E-11 PTR-ToF-MS 2-Norbornene Atkinson et al., 1983 0.76 97.1012 C7H12 7.98E-11 PTR-ToF-MS 1-methyl-cyclohexene; average Aschmann et al., 2012; 2.27 C7 dienes cycloheptene; 2-methyl-1,5- Atkinson and Arey, 2003; hexadiene; 2,4-dimethyl-1,3- Grosjean and Williams, 1992 pentadiene 109.1012 C8H12 1.07E-10 PTR-ToF-MS Bicyclo[2.2.2]oct-2-ene; average Atkinson and Arey, 2003; 3.82 1,2,3- Grosjean and Williams, 1992 Trimethylcyclopentadiene 111.1169 C8H14 1.20E-10 PTR-ToF-MS Z-Cyclooctene; 2,5-Dimethyl- Aschmann et al., 2012; 1.89 C8 dienes 2,4-hexadiene; 2,5-Dimethyl- Atkinson and Arey, 2003 1,5-hexadiene 137.1325 C10H16 3.73E-10 PTR-ToF-MS 1,3,7-Octatriene; α-Pinene average IUPAC preferred value; 3.07 Peeters et al., 2007 205.1951 C15H24 1.01E-10 PTR-ToF-MS β-caryophyllene; α-copaene; Atkinson and Arey, 2003; 1.10 Sesquiterpenes α-cedrene; α-humulene; E-β- IUPAC preferred values farnesene; Longifolene Aromatic Compounds m- and p-Xylene C8H10 1.87E-11 GC-FID average Atkinson and Arey, 2003 0.26 69.0335 C4H4O 4.04E-11 PTR-ToF-MS Furan Atkinson, 1986 0.28 Benzene C6H6 1.20E-12 GC-FID IUPAC preferred value 0.03 80.0495 C5H5N 5.31E-13 PTR-ToF-MS Pyridine Yeung and Elrod, 2003 0.002 83.0492 C5H6O 9.00E-11 PTR-ToF-MS 3-methyl-furan Atkinson et al., 1989 0.79 Toluene C7H8 5.60E-12 GC-FID IUPAC preferred value 0.23 94.0652 C6H7N 5.68E-11 PTR-ToF-MS Aniline; 4-methyl-pyridine; 3- average of Witte et al., 1986; Yeung and 0.32 methyl-pyridine; 2-methyl- methylpyridines and Elrod, 2003 pyridine aniline rate coefficients 95.0492 C6H6O 2.80E-11 PTR-ToF-MS Phenol IUPAC preferred value 0.87 97.0648 C6H8O 1.25E-10 PTR-ToF-MS 2,5-dimethylfuran Aschmann et al., 2011 0.86 105.0731 C8H8 5.80E-11 PTR-ToF-MS Styrene Atkinson and Arey, 2003 0.66 107.0492 C7H6O 1.26E-11 PTR-ToF-MS Benzaldehyde IUPAC preferred value 0.23 107.0855 C8H10 1.36E-11 PTR-ToF-MS o-Xylene Atkinson and Arey, 2003 0.35 m- and p-Xylene mixing ratios measured by GC- FID were subtracted 108.0808 C7H9N 9.60E-12 PTR-ToF-MS 2,6-dimethylpyridine; 2,4- average Yeung and Elrod, 2003 0.20 dimethylpyridine; 2,3- dimethylpyridine; 2,5- dimethylpyridine 119.0856 C9H10 5.95E-11 PTR-ToF-MS α-methylstyrene; β- average Bignozzi et al., 1981 0.72 methylstyrene 121.0648 C8H8O 1.61E-11 PTR-ToF-MS 4-methylbenzaldehyde; 3- average Clifford et al., 2005; 0.20 methylbenzaldehyde; 2- Aschmann et al., 2010 methylbenzaldehyde; acetophenone 121.1012 C9H12 5.70E-11 PTR-ToF-MS 1,3,5-trimethylbenzene Atkinson and Arey, 2003 0.91 123.0441 C7H6O2 1.20E-12 PTR-ToF-MS benzoic acid rate coefficient of IUPAC preferred value 0.005 benzene 125.0961 C8H12O 4.04E-11 PTR-ToF-MS 2,3,4,5-tetramethylfuran rate coefficient of Atkinson, 1986 0.14 furan 129.0699 C10H8 2.30E-11 PTR-ToF-MS Naphthalene Atkinson and Arey, 2003 0.07 131.0856 C10H10 2.30E-11 PTR-ToF-MS Dihydronaphthalene rate coefficient of Atkinson and Arey, 2003 0.07 naphthalene 133.1012 C10H12 3.37E-11 PTR-ToF-MS Tetralin; 2-methyl-1- average Atkinson and Arey, 2003; 0.19 propenylbenzene Chiorboli et al., 1983 135.0805 C9H10O 3.0E-11 PTR-ToF-MS Dimethylbenzaldehyde average Tse et al., 1997; Aschmann et 0.18 al., 2010 135.1169 C10H14 3.70E-11 PTR-ToF-MS tert-butylbenzene; p-cymene; average Alarcón et al., 2015; Atkinson 1.02 1,2,3,5-tetramethylbenzene; and Arey, 2003 1,2,3,4-tetramethylbenzene 143.0856 C11H10 5.08E-11 PTR-ToF-MS 2-methyl-Naphthalene; 1- average Atkinson and Aschmann, 0.94 methyl-naphthalene 1986; Phousongphouang and Arey, 2002 147.1169 C11H14 5.80E-11 PTR-ToF-MS 4-isopropyl styrene; 3- rate coefficient of Atkinson and Arey, 2003 1.15 pentenyl benzene styrene 149.1325 C11H16 1.10E-10 PTR-ToF-MS Pentamethylbenzene Alarcón et al., 2015 2.23 161.1325 C12H16 5.80E-11 PTR-ToF-MS 4-tert-butylstyrene rate coefficient of Atkinson and Arey, 2003 1.31 styrene 163.1482 C12H18 1.13E-10 PTR-ToF-MS Hexamethylbenzene Atkinson and Arey, 2003 1.30 175.1482 C13H18 3.85E-11 PTR-ToF-MS 1-2,2-dimethyl-1- average of indan and Atkinson and Arey, 2003 1.02 methylenepropyl-4-methyl- styrene rate benzene; 2-tert-butyl-indan coefficients 189.1638 C14H20 4.60E-11 PTR-ToF-MS 3,5-dimethyl-t-butylstyrene; average of styrene Atkinson and Arey, 2003 0.591 1-t-butyltetralin and tetralin rate coefficients 197.1325 C15H16 4.15E-12 PTR-ToF-MS 1,1'-1,3-propanediylbis- average of benzene Atkinson and Arey, 2003; 0.003 Benzene; 4-1-methylethyl- and biphyenyl IUPAC preferred value 1,1'-Biphenyl 199.1482 C15H18 2.30E-11 PTR-ToF-MS substituted naphthalenes rate coefficient of Atkinson and Arey, 2003 0.05 naphthalene OVOCs Formaldehyde HCHO 8.50E-12 Aerolaser IUPAC preferred value 2.33 Hantzsch 33.0335 CH3OH 9.00E-13 PTR-ToF-MS Methanol IUPAC preferred value 0.24 45.0335 C2H4O 1.50E-11 PTR-ToF-MS Acetaldehyde IUPAC preferred value 2.21 47.0128 HCOOH 4.50E-13 PTR-ToF-MS Formic acid IUPAC preferred value 0.07 57.0335 C3H4O 1.13E-11 PTR-ToF-MS Acrolein Atkinson and Arey, 2003 1.51 59.0491 C3H6O 1.80E-13 PTR-ToF-MS Acetone IUPAC preferred value 0.16 61.0285 C2H4O2 6.90E-13 PTR-ToF-MS Acetic acid IUPAC preferred value 0.13 63.0441 C2H6O2 1.45E-11 PTR-ToF-MS 1,2-ethanediol IUPAC preferred value 0.18 65.0233 CH4O3 7.10E-12 PTR-ToF-MS Hydroxymethyl Allen et al., 2018 0.14 hydroperoxide 71.0491 C4H6O 2.45E-11 PTR-ToF-MS Methyl vinyl ketone; average IUPAC preferred values; St 0.42 methacroleine; isoprene Clair et al., 2016 hydroxy hydroperoxide 73.0284 C3H4O2 1.30E-11 PTR-ToF-MS Methyl glyoxal IUPAC preferred value 0.21 73.0648 C4H8O 4.87E-11 PTR-ToF-MS Butanal; 2-methyl-propanal; average IUPAC preferred value; 1.80 C4 carbonyls tetrahydrofuran; 2-butanone Moriarty et al., 2003; Audley (MEK); ethoxy ethene et al., 1981; Zhou et al., 2006 75.0441 C3H6O2 2.85E-12 PTR-ToF-MS Hydroxyacetone; propanoic average IUPAC preferred values 0.10 acid 77.0598 C3H8O2 1.62E-11 PTR-ToF-MS 2-methoxyethanol; 1,2- IUPAC preferred value, Porter 0.07 propanediol et al., 1997 85.0648 C5H8O 4.43E-11 PTR-ToF-MS Cyclopentanone; E-2- average Atkinson and Arey, 2003; 0.52 pentenal; 3-methyl-3-buten-2- Grosjean and Williams, 1992; one; E-2-methyl-2-butenal; 3- Jiménez et al., 2009; Davis et methyl-2-butenal; 3-penten-2- al., 2007 one; 1-penten-3-one; 3,6- dihydro-2H-pyran 87.0441 C4H6O2 2.40E-11 PTR-ToF-MS 2,3-Butanedione; acetic acid average Baker et al., 2005a; Teruel et 0.61 C4 dioxygenates ethenyl ester; 2-propenoic acid al., 2006; Blanco et al., 2009; methyl ester; 4-hydroxy-2- Dagaut et al., 1988 butenal 87.0805 C5H10O 4.63E-11 PTR-ToF-MS Pentanal; 3-methyl-2- average Zhou et al., 2006; IUPAC; 2.48 butanone; 3-pentanone; 2- Cometto et al., 2008; Atkinson pentanone; 1- and Arey, 2003; Orlando et vinyloxypropane; 2-Methyl-3- al., 2001 buten-2-ol MBO; 3-methyl-3- buten-1-ol; 2-methylbutanal; 3-methylbutanal; 1-penten-3- ol; Z-2-penten-1-ol 89.0234 C3H4O3 1.20E-13